Tools such as MRTG provide network throughput / bandwidth graphs for the current network utilisation on specific interfaces, such as eth0. How can I return that information at the command line on Linux/UNIX?
Preferably this would be without installing anything other than what is available on the system as standard.
This question is related to
linux
networking
bandwidth
ifconfig -a
ip -d link
ls -l /sys/class/net/ (physical and virtual devices)
route -n
If you want the output of (ifconfig -a) in json format you can use this (python)
I find dstat to be quite good. Has to be installed though. Gives you way more information than you need. Netstat will give you packet rates but not bandwith also. netstat -s
Besides iftop and iptraf, also check:
bwm-ng (Bandwidth Monitor Next Generation)and/or
cbm (Color Bandwidth Meter)ref: http://www.powercram.com/2010/01/bandwidth-monitoring-tools-for-ubuntu.html
iftop does for network usage what top(1) does for CPU usage -- http://www.ex-parrot.com/~pdw/iftop/
I don't know how "standard" iftop is, but I was able to install it with yum install iftop on Fedora.
If you want just to get the value, you can use simple shell oneliner like this:
S=10; F=/sys/class/net/eth0/statistics/rx_bytes; X=`cat $F`; sleep $S; Y=`cat $F`; BPS="$(((Y-X)/S))"; echo $BPS
It will show you the average "received bytes per second" for period of 10 seconds (you can change period by changing S=10 parameter, and you can measure transmitted BPS instead of received BPS by using tx_bytes instead of rx_bytes). Don't forget to change eth0 to network device you want to monitor.
Of course, you are not limited to displaying the average rate (as mentioned in other answers, there are other tools that will show you much nicer output), but this solution is easily scriptable to do other things.
For example, the following shell script (split into multiple lines for readability) will execute offlineimap process only when 5-minute average transmit speed drops below 10kBPS (presumably, when some other bandwidth-consuming process finishes):
#!/bin/sh
S=300; F=/sys/class/net/eth0/statistics/tx_bytes
BPS=999999
while [ $BPS -gt 10000 ]
do
X=`cat $F`; sleep $S; Y=`cat $F`; BPS="$(((Y-X)/S))";
echo BPS is currently $BPS
done
offlineimap
Note that /sys/class/... is Linux specific (which is ok as submitter did choose linux tag), and needs non-archaic kernel. Shell code itself is /bin/sh compatible (so not only bash, but dash and other /bin/sh implementations will work) and /bin/sh is something that is really always installed.
You can use iperf to benchmark network performance (maximum possible throughput). See following links for details:
Got sar? Likely yes if youre using RHEL/CentOS.
No need for priv, dorky binaries, hacky scripts, libpcap, etc. Win.
$ sar -n DEV 1 3
Linux 2.6.18-194.el5 (localhost.localdomain) 10/27/2010
02:40:56 PM IFACE rxpck/s txpck/s rxbyt/s txbyt/s rxcmp/s txcmp/s rxmcst/s
02:40:57 PM lo 0.00 0.00 0.00 0.00 0.00 0.00 0.00
02:40:57 PM eth0 10700.00 1705.05 15860765.66 124250.51 0.00 0.00 0.00
02:40:57 PM eth1 0.00 0.00 0.00 0.00 0.00 0.00 0.00
02:40:57 PM IFACE rxpck/s txpck/s rxbyt/s txbyt/s rxcmp/s txcmp/s rxmcst/s
02:40:58 PM lo 0.00 0.00 0.00 0.00 0.00 0.00 0.00
02:40:58 PM eth0 8051.00 1438.00 11849206.00 105356.00 0.00 0.00 0.00
02:40:58 PM eth1 0.00 0.00 0.00 0.00 0.00 0.00 0.00
02:40:58 PM IFACE rxpck/s txpck/s rxbyt/s txbyt/s rxcmp/s txcmp/s rxmcst/s
02:40:59 PM lo 0.00 0.00 0.00 0.00 0.00 0.00 0.00
02:40:59 PM eth0 6093.00 1135.00 8970988.00 82942.00 0.00 0.00 0.00
02:40:59 PM eth1 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Average: IFACE rxpck/s txpck/s rxbyt/s txbyt/s rxcmp/s txcmp/s rxmcst/s
Average: lo 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Average: eth0 8273.24 1425.08 12214833.44 104115.72 0.00 0.00 0.00
Average: eth1 0.00 0.00 0.00 0.00 0.00 0.00 0.00
I couldn't get the parse ifconfig script to work for me on an AMI so got this to work measuring received traffic averaged over 10 seconds
date && rxstart=`ifconfig eth0 | grep bytes | awk '{print $2}' | cut -d : -f 2` && sleep 10 && rxend=`ifconfig eth0 | grep bytes | awk '{print $2}' | cut -d : -f 2` && difference=`expr $rxend - $rxstart` && echo "Received `expr $difference / 10` bytes per sec"
Sorry, it's ever so cheap and nasty but it worked!
dstat - Combines vmstat, iostat, ifstat, netstat information and more iftop - Amazing network bandwidth utility to analyse what is really happening on your eth netio - Measures the net throughput of a network via TCP/IP inq - CLI troubleshooting utility that displays info on storage, typically Symmetrix. By default, INQ returns the device name, Symmetrix ID, Symmetrix LUN, and capacity.send_arp - Sends out an arp broadcast on the specified network device (defaults to eth0), reporting an old and new IP address mapping to a MAC address.EtherApe - is a graphical network monitor for Unix modeled after etherman. Featuring link layer, IP and TCP modes, it displays network activity graphically.iptraf - An IP traffic monitor that shows information on the IP traffic passing over your network.More details: http://felipeferreira.net/?p=1194
I like iptraf but you probably have to install it and it seems to not being maintained actively anymore.
nload is a great tool for monitoring bandwidth in real time and easily installed in Ubuntu or Debian with sudo apt-get install nload.
Device eth0 [10.10.10.5] (1/2):
=====================================================================================
Incoming:
. ...|
# ####|
.. |#| ... #####. .. Curr: 2.07 MBit/s
###.### #### #######|. . ## | Avg: 1.41 MBit/s
########|#########################. ### Min: 1.12 kBit/s
........ ################################### .### Max: 4.49 MBit/s
.##########. |###################################|##### Ttl: 1.94 GByte
Outgoing:
########## ########### ###########################
########## ########### ###########################
##########. ########### .###########################
########### ########### #############################
########### ###########..#############################
############ ##########################################
############ ##########################################
############ ########################################## Curr: 63.88 MBit/s
############ ########################################## Avg: 32.04 MBit/s
############ ########################################## Min: 0.00 Bit/s
############ ########################################## Max: 93.23 MBit/s
############## ########################################## Ttl: 2.49 GByte
Another excellent tool is iftop, also easily apt-get'able:
191Mb 381Mb 572Mb 763Mb 954Mb
+--------------------------------------------------------------------------------
box4.local => box-2.local 91.0Mb 27.0Mb 15.1Mb
<= 1.59Mb 761kb 452kb
box4.local => box.local 560b 26.8kb 27.7kb
<= 880b 31.3kb 32.1kb
box4.local => userify.com 0b 11.4kb 8.01kb
<= 1.17kb 2.39kb 1.75kb
box4.local => b.resolvers.Level3.net 0b 58b 168b
<= 0b 83b 288b
box4.local => stackoverflow.com 0b 42b 21b
<= 0b 42b 21b
box4.local => 224.0.0.251 0b 0b 179b
<= 0b 0b 0b
224.0.0.251 => box-2.local 0b 0b 0b
<= 0b 0b 36b
224.0.0.251 => box.local 0b 0b 0b
<= 0b 0b 35b
---------------------------------------------------------------------------------
TX: cum: 37.9MB peak: 91.0Mb rates: 91.0Mb 27.1Mb 15.2Mb
RX: 1.19MB 1.89Mb 1.59Mb 795kb 486kb
TOTAL: 39.1MB 92.6Mb 92.6Mb 27.9Mb 15.6Mb
Don't forget about the classic and powerful sar and netstat utilities on older *nix!
I got another quick'n'dirty bash script for that:
#!/bin/bash
IF=$1
if [ -z "$IF" ]; then
IF=`ls -1 /sys/class/net/ | head -1`
fi
RXPREV=-1
TXPREV=-1
echo "Listening $IF..."
while [ 1 == 1 ] ; do
RX=`cat /sys/class/net/${IF}/statistics/rx_bytes`
TX=`cat /sys/class/net/${IF}/statistics/tx_bytes`
if [ $RXPREV -ne -1 ] ; then
let BWRX=$RX-$RXPREV
let BWTX=$TX-$TXPREV
echo "Received: $BWRX B/s Sent: $BWTX B/s"
fi
RXPREV=$RX
TXPREV=$TX
sleep 1
done
It's considering that sleep 1 will actually last exactly one second, which is not true, but good enough for a rough bandwidth assessment.
Thanks to @ephemient for the /sys/class/net/<interface>! :)
I wrote this dumb script a long time ago, it depends on nothing but Perl and Linux≥2.6:
#!/usr/bin/perl
use strict;
use warnings;
use POSIX qw(strftime);
use Time::HiRes qw(gettimeofday usleep);
my $dev = @ARGV ? shift : 'eth0';
my $dir = "/sys/class/net/$dev/statistics";
my %stats = do {
opendir +(my $dh), $dir;
local @_ = readdir $dh;
closedir $dh;
map +($_, []), grep !/^\.\.?$/, @_;
};
if (-t STDOUT) {
while (1) {
print "\033[H\033[J", run();
my ($time, $us) = gettimeofday();
my ($sec, $min, $hour) = localtime $time;
{
local $| = 1;
printf '%-31.31s: %02d:%02d:%02d.%06d%8s%8s%8s%8s',
$dev, $hour, $min, $sec, $us, qw(1s 5s 15s 60s)
}
usleep($us ? 1000000 - $us : 1000000);
}
}
else {print run()}
sub run {
map {
chomp (my ($stat) = slurp("$dir/$_"));
my $line = sprintf '%-31.31s:%16.16s', $_, $stat;
$line .= sprintf '%8.8s', int (($stat - $stats{$_}->[0]) / 1)
if @{$stats{$_}} > 0;
$line .= sprintf '%8.8s', int (($stat - $stats{$_}->[4]) / 5)
if @{$stats{$_}} > 4;
$line .= sprintf '%8.8s', int (($stat - $stats{$_}->[14]) / 15)
if @{$stats{$_}} > 14;
$line .= sprintf '%8.8s', int (($stat - $stats{$_}->[59]) / 60)
if @{$stats{$_}} > 59;
unshift @{$stats{$_}}, $stat;
pop @{$stats{$_}} if @{$stats{$_}} > 60;
"$line\n";
} sort keys %stats;
}
sub slurp {
local @ARGV = @_;
local @_ = <>;
@_;
}
It just reads from /sys/class/net/$dev/statistics every second, and prints out the current numbers and the average rate of change:
$ ./net_stats.pl eth0
rx_bytes : 74457040115259 4369093 4797875 4206554 364088
rx_packets : 91215713193 23120 23502 23234 17616
...
tx_bytes : 90798990376725 8117924 7047762 7472650 319330
tx_packets : 93139479736 23401 22953 23216 23171
...
eth0 : 15:22:09.002216 1s 5s 15s 60s
^ current reading ^-------- averages ---------^
You could parse /proc/net/dev.
Source: Stackoverflow.com